Information transmission method, network device, and user equipment

ABSTRACT

Embodiments of this application provide an information transmission method, a network device, and a user equipment. The method provided in this application includes: sending, by a network device, a broadcast frame that includes first duration information and second duration information that are of A-BFT (Association Beamforming Training); receiving a frame sent by a first user equipment in a timeslot randomly selected from a first time range; and receiving a frame sent by a second user equipment in a timeslot randomly selected from a second time range. According to the embodiments of this application, beamforming training efficiency can be improved.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/206,288, filed on Nov. 30, 2018, which is a continuation ofInternational Application No. PCT/CN2017/082325, filed on Apr. 28, 2017,which claims priority to Chinese Patent Application No. 201610482072.3,filed on Jun. 27, 2016 and Chinese Patent Application No.201610394650.8, filed on Jun. 3, 2016. All of the afore-mentioned patentapplications are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

Embodiments of this application relate to communications technologies,and in particular, to an information transmission method, a networkdevice, and a user equipment.

BACKGROUND

Currently, a wireless local area network (WLAN) usually operates in 2.4GHz and 5 GHz frequency bands. Spectrum resources on the frequency bandsbecome extremely crowded as a quantity of devices that use the frequencybands increases. However, a 60 GHz millimeter wave band has a largequantity of available spectrum resources. Therefore, the 60 GHzfrequency band will be widely used in the future. Because a path loss ofthe 60 GHz millimeter wave band is extremely large, a communicationdistance based on the 60 GHz millimeter wave band is usually relativelyshort. To increase the communication distance, by using a directionalcommunications technology of beamforming (BF), a transmit signal of atransmit antenna may center on an extremely small narrow beam, and areceive antenna receives the signal in an extremely narrow beam range.Before a BF technology is used, a network device may send a directionalmulti-gigabit (DMG) beacon frame in a beacon transmission interval (BTI)within a beacon interval (BI). The DMG beacon frame may include durationof association beamforming training (A-BFT) in the BI. Each userequipment in at least one user equipment that receives the DMG beaconframe sends a sector sweep (SSW) frame to the network device in atimeslot randomly selected in the duration of the A-BFT, so as toimplement beamforming training of the user equipment.

With continuous development of communications technologies, a quantityand a type of user equipment continuously increase. However, currently,a network device may implement beamforming training of user equipment ofone type in same A-BFT. This results in relatively low efficiency ofbeamforming training of the user equipment.

SUMMARY

Embodiments of this application provide an information transmissionmethod, a network device, and a user equipment, so as to improvebeamforming training efficiency.

According to an aspect, an embodiment of this application provides aninformation transmission method, including:

-   -   sending, by a network device, a broadcast frame, where the        broadcast frame includes first duration information and second        duration information that are of association beamforming        training A-BFT; the first duration information is used by a        first user equipment to determine a first time range, so that        the first user equipment randomly selects a timeslot from the        first time range; and the second duration information is used by        a second user equipment to determine a second time range, so        that the second user equipment randomly selects a timeslot from        the second time range;    -   receiving, by the network device, a first-type frame sent by the        first user equipment in the timeslot randomly selected from the        first time range; and    -   receiving, by the network device, a second-type frame sent by        the second user equipment in the timeslot randomly selected from        the second time range.

According to the information transmission method, the network device mayimplement beamforming training of user equipments of multiple accesstypes in same A-BFT, so as to improve beamforming training efficiencyand improve a network throughput.

Optionally, the first duration information includes duration of thefirst time range; and

-   -   the duration of the first time range is used by the first user        equipment to determine an end time of the first time range        according to a preset start time and the duration of the first        time range, and determine the first time range according to the        preset start time and the end time of the first time range.

Optionally, the second duration information includes duration of thesecond time range;

-   -   the duration of the first time range is further used by the        second user equipment to determine a start time of the second        time range according to the duration of the first time range;        and    -   the duration of the second time range is used by the second user        equipment to determine an end time of the second time range        according to the start time of the second time range and the        duration of the second time range, and determine the second time        range according to the start time of the second time range and        the end time of the second time range.

Optionally, the second duration information includes duration of thesecond time range; and

-   -   the duration of the second time range is used by the second user        equipment to determine an end time of the second time range        according to the preset start time and the duration of the        second time range, and determine the second time range according        to the preset start time and the end time of the second time        range.

In the information transmission method, both a start time of the firsttime range and the start time of the second time range may be the presetstart time. Therefore, the first time range and the second time rangemay have a partially-overlapped time, and the duration of the secondtime range may be greater than the duration of the first time range, sothat a time selection range of the second user equipment is greater thana time selection range of the first user equipment, thereby effectivelyavoiding an access timeslot conflict of the second user equipment, andimproving timeslot resource utilization.

Optionally, the duration of the first time range is located in an A-BFTlength field of a beacon interval BI control field in the broadcastframe; and

-   -   the duration of the second time range is located in any one of        the following locations in the broadcast frame:    -   at least one bit in the BI control field except the A-BFT length        field; or    -   a preset field or information element in a data payload field,        where the preset field or information element includes at least        one bit.

Optionally, the broadcast frame further includes frame type indicationinformation, and the frame type indication information is used by thesecond user equipment to determine a frame type; and

-   -   the receiving, by the network device, a second-type frame sent        by the second user equipment in the timeslot randomly selected        from the second time range includes:    -   receiving, by the network device, the second-type frame that is        corresponding to the frame type and sent by the second user        equipment in the timeslot randomly selected from the second time        range, where transmission duration of frames corresponding to        different frame types is different.

Optionally, the frame type indication information is located in at leastone reserved bit in a directional multi-gigabit DMG parameters field inthe broadcast frame.

Optionally, the broadcast frame further includes frame quantityindication information, and the frame quantity indication information isused by the second user equipment to determine a frame quantity; and

-   -   the receiving, by the network device, a second-type frame sent        by the second user equipment in the timeslot randomly selected        from the second time range includes:    -   receiving, by the network device, the frame quantity of the        second-type frames successively sent by the second user        equipment in the timeslot randomly selected from the second time        range.

Optionally, the broadcast frame further includes usage indicationinformation of at least one channel, and the usage indicationinformation of the at least one channel is used by the second userequipment to determine whether the at least one channel is available, sothat the second user equipment selects an available channel from the atleast one channel; and

-   -   the receiving, by the network device, a second-type frame sent        by the second user equipment in the timeslot randomly selected        from the second time range includes:    -   receiving, by the network device, the second-type frame sent by        the second user equipment through the available channel in the        timeslot randomly selected from the second time range.

Optionally, the receiving, by the network device, the second-type framesent by the second user equipment through the available channel in thetimeslot randomly selected from the second time range includes:

-   -   if the available channel is a main channel, receiving, by the        network device, the second-type frame sent by the second user        equipment through the available channel in the timeslot randomly        selected from the second time range.

Optionally, the broadcast frame further includes duration informationcorresponding to each channel, and the duration informationcorresponding to each channel is used by the second user equipment todetermine a time range corresponding to each channel, so that if theavailable channel is a secondary channel, the second user equipmentrandomly selects a timeslot from a time range corresponding to theavailable channel; and

-   -   the method may further include:    -   receiving, by the network device, the second-type frame sent by        the second user equipment through the available channel in the        timeslot randomly selected from the time range corresponding to        the available channel.

Optionally, the usage indication information of the at least one channeland/or the duration information corresponding to each channel are/islocated in any one of the following locations in the broadcast frame:

-   -   at least one reserved bit of a DMG operation information field        in a DMG operation element; or    -   a preset field or information element in a data payload field,        where the preset field or information element includes at least        one bit.

Optionally, the second duration information is specifically used by thesecond user equipment to determine the second time range, so that thesecond user equipment randomly selects a timeslot from the second timerange, and randomly selects backoff duration in the randomly selectedtimeslot; and

-   -   the receiving, by the network device, a second-type frame sent        by the second user equipment in the timeslot randomly selected        from the second time range includes:    -   receiving, by the network device, the second-type frame sent by        the second user equipment after the backoff duration in the        timeslot randomly selected from the second time range.

According to the information transmission method, after randomlyselecting the timeslot from the second time range, the second userequipment may further select the backoff duration, and send thesecond-type frame after the backoff duration, so as to effectivelyreduce a timeslot conflict between second user equipments and improvetraining efficiency of the A-BFT.

Optionally, backoff duration is determined by the second user equipmentaccording to an access priority corresponding to the second userequipment, a higher access priority corresponding to the second userequipment indicates shorter backoff duration, and a lower accesspriority corresponding to the second user equipment indicates longerbackoff duration.

Optionally, a larger quantity of access failures of the second userequipment indicates a higher access priority corresponding to the seconduser equipment.

According to the information transmission method, in a dense scenario, atimeslot conflict that occurs during an A-BFT period when multiple userequipments perform beamforming training may be reduced, so that userequipment that still cannot perform access after multiple trainingperiods quickly accesses the network device, to quickly completebeamforming training, thereby improving training timeliness, andimproving user experience.

Optionally, before the sending, by a network device, a frame, the methodfurther includes:

-   -   determining, by the network device, whether a quantity of        to-be-accessed user equipments is greater than a preset quantity        value; and    -   the sending, by a network device, a broadcast frame includes:    -   sending, by the network device, the broadcast frame if the        quantity of user equipments is greater than or equal to the        preset quantity value.

Optionally, the broadcast frame includes overload indicator information,and the overload indicator information is located in any one of thefollowing locations:

-   -   a reserved bit of a beacon interval BI control field in a frame        control field; or    -   a reserved bit of another field other than the BI control field.

According to another aspect, an embodiment of this application furtherprovides an information transmission method, including:

-   -   receiving, by a second user equipment, a broadcast frame sent by        a network device, where the broadcast frame includes first        duration information and second duration information that are of        association beamforming training A-BFT, and the first duration        information is used by a first user equipment to determine a        first time range, so that the first user equipment randomly        selects a timeslot from the first time range, so as to send a        first-type frame to the network device in the timeslot randomly        selected from the first time range;    -   determining, by the second user equipment, a second time range        according to the second duration information, and randomly        selecting a timeslot from the second time range; and    -   sending, by the second user equipment, a second-type frame to        the network device in the timeslot randomly selected from the        second time range.

Optionally, the first duration information includes duration of thefirst time range, and the second duration information includes durationof the second time range; and

-   -   the determining, by the second user equipment, a second time        range according to the second duration information includes:    -   determining, by the second user equipment, a start time of the        second time range according to the duration of the first time        range;    -   determining, by the second user equipment, an end time of the        second time range according to the start time of the second time        range and the duration of the second time range; and    -   determining, by the second user equipment, the second time range        according to the start time of the second time range and the end        time of the second time range.

Optionally, the second duration information includes duration of thesecond time range; and

-   -   the determining, by the second user equipment, a second time        range according to the second duration information includes:    -   determining, by the second user equipment, an end time of the        second time range according to a preset start time and the        duration of the second time range, where the preset start time        is a preset start time of the first time range; and    -   determining, by the second user equipment, the second time range        according to the preset start time and the end time of the        second time range.

Optionally, the duration of the first time range is located in an A-BFTlength field of a beacon interval BI control field in the broadcastframe; and

-   -   the duration of the second time range is located in any one of        the following locations in the broadcast frame:    -   at least one reserved bit in the BI control field except the        A-BFT length field; or    -   a preset field or information element in a data payload field,        where the preset field or information element includes at least        one bit.

Optionally, the broadcast frame further includes frame type indicationinformation;

-   -   before the sending, by the second user equipment, a second-type        frame to the network device in the timeslot randomly selected        from the second time range, the method may further include:    -   determining, by the second user equipment, a frame type        according to the frame type indication information; and    -   the sending, by the second user equipment, a second-type frame        to the network device in the timeslot randomly selected from the        second time range includes:    -   sending, by the second user equipment to the network device in        the timeslot randomly selected from the second time range, the        second-type frame corresponding to the frame type, where        transmission duration of frames corresponding to different frame        types is different.

Optionally, the frame type indication information is located in at leastone reserved bit in a directional multi-gigabit DMG parameters field inthe broadcast frame.

Optionally, the broadcast frame further includes frame quantityindication information;

-   -   before the sending, by the second user equipment, a second-type        frame to the network device in the timeslot randomly selected        from the second time range, the method further includes:    -   determining, by the second user equipment, a quantity of        to-be-sent frames according to the frame quantity indication        information; and    -   the sending, by the second user equipment, a second-type frame        to the network device in the timeslot randomly selected from the        second time range includes:    -   successively sending, by the second user equipment, the frame        quantity of the second-type frames to the network device in the        timeslot randomly selected from the second time range.

Optionally, the broadcast frame further includes usage indicationinformation of at least one channel; and

-   -   the sending, by the second user equipment, a second-type frame        to the network device in the timeslot randomly selected from the        second time range includes:    -   determining, by the second user equipment according to the usage        indication information of the at least one channel, whether the        at least one channel is available; and selecting an available        channel from the at least one channel; and    -   sending, by the second user equipment, the second-type frame to        the network device through the available channel in the timeslot        randomly selected from the second time range.

Optionally, the sending, by the second user equipment, the second-typeframe to the network device through the available channel in thetimeslot randomly selected from the second time range includes:

-   -   if the available channel is a main channel, sending, by the        second user equipment, the second-type frame to the network        device through the available channel in the timeslot randomly        selected from the second time range.

Optionally, the broadcast frame further includes duration informationcorresponding to each channel; and

-   -   the method further includes:    -   if the available channel is a secondary channel, determining, by        the second user equipment according to duration information        corresponding to the available channel, a time range        corresponding to the available channel;    -   randomly selecting, by the second user equipment, a timeslot        from the time range corresponding to the available channel; and    -   sending, by the second user equipment, the second-type frame        through the available channel in the timeslot randomly selected        from the time range corresponding to the available channel.

Optionally, the usage indication information of the at least one channeland/or the duration information corresponding to each channel are/islocated in any one of the following locations in the broadcast frame:

-   -   at least one reserved bit of a DMG operation information field        in a DMG operation element; or    -   a preset field or information element in a data payload field,        where the preset field or information element includes at least        one bit.

Optionally, before the sending, by the second user equipment, asecond-type frame to the network device in the timeslot randomlyselected from the second time range includes:

-   -   randomly selecting, by the second user equipment, backoff        duration in the timeslot randomly selected from the second time        range; and    -   the sending, by the second user equipment, a second-type frame        to the network device in the timeslot randomly selected from the        second time range includes:    -   sending, by the second user equipment, the second-type frame to        the network device after the backoff duration in the timeslot        randomly selected from the second time range.

Optionally, before the sending, by the second user equipment, asecond-type frame to the network device in the timeslot randomlyselected from the second time range, the method further includes:

-   -   determining, by the second user equipment according to an access        priority of the second user equipment, backoff duration        corresponding to the access priority, where a higher access        priority indicates shorter backoff duration, and a lower access        priority indicates longer backoff duration; and    -   the sending, by the second user equipment, a second-type frame        to the network device in the timeslot randomly selected from the        second time range includes:    -   sending, by the second user equipment, the second-type frame to        the network device after the backoff duration in the timeslot        randomly selected from the second time range.

Optionally, before the determining, by the second user equipmentaccording to an access priority of the second user equipment, backoffduration corresponding to the access priority, the method furtherincludes:

-   -   determining, by the second user equipment, the access priority        according to a quantity of access failures of the second user        equipment, where a larger quantity of access failures indicates        a higher access priority.

According to still another aspect, an embodiment of this applicationprovides a network device, including a transmitter and a receiver, where

-   -   the transmitter is configured to send a broadcast frame, where        the broadcast frame includes first duration information and        second duration information that are of association beamforming        training A-BFT; the first duration information is used by a        first user equipment to determine a first time range, so that        the first user equipment randomly selects a timeslot from the        first time range; and the second duration information is used by        a second user equipment to determine a second time range, so        that the second user equipment randomly selects a timeslot from        the second time range; and    -   the receiver is configured to: receive a first-type frame sent        by the first user equipment in the timeslot randomly selected        from the first time range; and receive a second-type frame sent        by the second user equipment in the timeslot randomly selected        from the second time range.

Optionally, the first duration information includes duration of thefirst time range; and

-   -   the duration of the first time range is used by the first user        equipment to determine an end time of the first time range        according to a preset start time and the duration of the first        time range, and determine the first time range according to the        preset start time and the end time of the first time range.

Optionally, the second duration information includes duration of thesecond time range;

-   -   the duration of the first time range is further used by the        second user equipment to determine a start time of the second        time range according to the duration of the first time range;        and    -   the duration of the second time range is used by the second user        equipment to determine an end time of the second time range        according to the start time of the second time range and the        duration of the second time range, and determine the second time        range according to the start time of the second time range and        the end time of the second time range.

Optionally, the second duration information includes duration of thesecond time range; and

-   -   the duration of the second time range is used by the second user        equipment to determine an end time of the second time range        according to the preset start time and the duration of the        second time range, and determine the second time range according        to the preset start time and the end time of the second time        range.

Optionally, the broadcast frame further includes frame type indicationinformation, and the frame type indication information is used by thesecond user equipment to determine a frame type; and

-   -   the receiver is specifically configured to receive the        second-type frame that is corresponding to the frame type and        sent by the second user equipment in the timeslot randomly        selected from the second time range, where transmission duration        of frames corresponding to different frame types is different.

Optionally, the broadcast frame further includes frame quantityindication information, and the frame quantity indication information isused by the second user equipment to determine a frame quantity; and

-   -   the receiver is specifically configured to receive the frame        quantity of the second-type frames successively sent by the        second user equipment in the timeslot randomly selected from the        second time range.

Optionally, the broadcast frame further includes usage indicationinformation of at least one channel, and the usage indicationinformation of the at least one channel is used by the second userequipment to determine whether the at least one channel is available, sothat the second user equipment selects an available channel from the atleast one channel; and

-   -   the receiver is further specifically configured to receive the        second-type frame sent by the second user equipment through the        available channel in the timeslot randomly selected from the        second time range.

Optionally, the receiver is further specifically configured to: if theavailable channel is a main channel, receive the second-type frame sentby the second user equipment through the available channel in thetimeslot randomly selected from the second time range.

Optionally, the broadcast frame further includes duration informationcorresponding to each channel, and the duration informationcorresponding to each channel is used by the second user equipment todetermine a time range corresponding to each channel, so that if theavailable channel is a secondary channel, the second user equipmentrandomly selects a timeslot from a time range corresponding to theavailable channel; and

-   -   the receiver is further configured to receive the second-type        frame sent by the second user equipment through the available        channel in the timeslot randomly selected from the time range        corresponding to the available channel.

Optionally, the second duration information is specifically used by thesecond user equipment to determine the second time range, so that thesecond user equipment randomly selects a timeslot from the second timerange, and randomly selects backoff duration in the randomly selectedtimeslot; and

-   -   the receiver is specifically configured to receive the        second-type frame sent by the second user equipment after the        backoff duration in the timeslot randomly selected from the        second time range.

Optionally, backoff duration is determined by the second user equipmentaccording to an access priority corresponding to the second userequipment, a higher access priority corresponding to the second userequipment indicates shorter backoff duration, and a lower accesspriority corresponding to the second user equipment indicates longerbackoff duration.

Optionally, a larger quantity of access failures of the second userequipment indicates a higher access priority corresponding to the seconduser equipment.

According to yet another aspect, an embodiment of this application mayfurther provide user equipment, where the user equipment is second userequipment, and includes a receiver, a processor, and a transmitter, thereceiver is connected to the processor, and the processor is connectedto the transmitter, where

-   -   the receiver is configured to receive a broadcast frame sent by        a network device, where the broadcast frame includes first        duration information and second duration information that are of        association beamforming training A-BFT, and the first duration        information is used by a first user equipment to determine a        first time range, so that the first user equipment randomly        selects a timeslot from the first time range, so as to send a        first-type frame to the network device in the timeslot randomly        selected from the first time range;    -   the processor is configured to determine a second time range        according to the second duration information, and randomly        select a timeslot from the second time range; and    -   the transmitter is configured to send a second-type frame to the        network device in the timeslot randomly selected from the second        time range.

Optionally, the first duration information includes duration of thefirst time range, and the second duration information includes durationof the second time range; and

-   -   the processor is specifically configured to: determine a start        time of the second time range according to the duration of the        first time range; determine an end time of the second time range        according to the start time of the second time range and the        duration of the second time range; and determine the second time        range according to the start time of the second time range and        the end time of the second time range.

Optionally, the second duration information includes duration of thesecond time range; and

-   -   the processor is further specifically configured to: determine        an end time of the second time range according to a preset start        time and the duration of the second time range, where the preset        start time is a preset start time of the first time range; and        determine the second time range according to the preset start        time and the end time of the second time range.

Optionally, the broadcast frame further includes frame type indicationinformation;

-   -   the processor is further configured to determine a frame type        according to the frame type indication information before the        transmitter sends the second-type frame to the network device in        the timeslot randomly selected from the second time range; and    -   the transmitter is specifically configured to send, to the        network device in the timeslot randomly selected from the second        time range, the second-type frame corresponding to the frame        type, where transmission duration of frames corresponding to        different frame types is different.

Optionally, the broadcast frame further includes frame quantityindication information;

-   -   the processor is further configured to determine a quantity of        to-be-sent frames according to the frame quantity indication        information before the transmitter sends the second-type frame        to the network device in the timeslot randomly selected from the        second time range; and    -   the transmitter is specifically configured to successively send        the frame quantity of the second-type frames to the network        device in the timeslot randomly selected from the second time        range.

Optionally, the broadcast frame further includes usage indicationinformation of at least one channel;

-   -   the processor is further configured to determine, according to        the usage indication information of the at least one channel,        whether the at least one channel is available; and select an        available channel from the at least one channel; and    -   the transmitter is specifically configured to send the        second-type frame to the network device through the available        channel in the timeslot randomly selected from the second time        range.

Optionally, the transmitter is specifically configured to: if theavailable channel is a main channel, send the second-type frame to thenetwork device through the available channel in the timeslot randomlyselected from the second time range.

Optionally, the broadcast frame further includes duration informationcorresponding to each channel;

-   -   the processor is further configured to: if the available channel        is a secondary channel, determine, according to duration        information corresponding to the available channel, a time range        corresponding to the available channel; and randomly select a        timeslot from the time range corresponding to the available        channel; and    -   the transmitter is further configured to send the second-type        frame through the available channel in the timeslot randomly        selected from the time range corresponding to the available        channel.

Optionally, the processor is further configured to: before thetransmitter sends the second-type frame to the network device in thetimeslot randomly selected from the second time range, randomly selectbackoff duration in the timeslot randomly selected from the second timerange; and

-   -   the transmitter is specifically configured to send the        second-type frame to the network device after the backoff        duration in the timeslot randomly selected from the second time        range.

Optionally, the processor is further configured to: before thetransmitter sends the second-type frame to the network device in thetimeslot randomly selected from the second time range, determine,according to an access priority of the second user equipment, backoffduration corresponding to the access priority, where a higher accesspriority indicates shorter backoff duration, and a lower access priorityindicates longer backoff duration; and

-   -   the transmitter is specifically configured to send the        second-type frame to the network device after the backoff        duration in the timeslot randomly selected from the second time        range.

Optionally, the processor is further configured to determine the accesspriority according to a quantity of access failures of the second userequipment, where a larger quantity of access failures indicates a higheraccess priority.

According to the information transmission method, the network device,and the user equipment that are provided in the embodiments of thisapplication, the network device sends the broadcast frame that includesthe first duration information and the second duration information thatare of the A-BFT, so that the first user equipment can determine thefirst time range according to the first duration information, andrandomly select the timeslot from the first time range, so as to sendthe first-type frame in the timeslot randomly selected from the firsttime range; and the second user equipment can determine the second timerange according to the second duration information, and randomly selectthe timeslot from the second time range, so as to send the second-typeframe in the timeslot randomly selected from the second time range.Therefore, the network device may implement beamforming training of thefirst user equipment and the second user equipment in the same A-BFT, soas to improve beamforming training efficiency and improve a networkthroughput.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic structural diagram of a network system applicableto embodiments of this application;

FIG. 2 is a flowchart of an information transmission method according toEmbodiment 1 of this application;

FIG. 3 is a flowchart in which first user equipment determines a firsttime range in an information transmission method according to Embodiment2 of this application;

FIG. 4 is a schematic structural diagram of a BI according to Embodiment2 of this application;

FIG. 5 is a flowchart in which second user equipment determines a secondtime range in an information transmission method according to Embodiment2 of this application;

FIG. 6 is a schematic structural diagram of another BI according toEmbodiment 2 of this application;

FIG. 7 is a flowchart of determining a second time range in aninformation transmission according to Embodiment 2 of this application;

FIG. 8 is a schematic structural diagram of still another BI accordingto Embodiment 2 of this application;

FIG. 9 is a schematic structural diagram of a next DMG ATI elementaccording to Embodiment 2 of this application;

FIG. 10 is a schematic structural diagram of an extended scheduleelement according to Embodiment 2 of this application;

FIG. 11 is a schematic structural diagram of a BI control fieldaccording to Embodiment 2 of this application;

FIG. 11A is a schematic structural diagram of yet another BI accordingto Embodiment 2 of the present application;

FIG. 11B is a schematic structural diagram of still yet another BIaccording to Embodiment 2 of the present application;

FIG. 12 is a schematic structural diagram of a broadcast frame accordingto Embodiment 2 of this application;

FIG. 13 is a flowchart of another information transmission methodaccording to Embodiment 2 of this application;

FIG. 14 is a schematic structural diagram of an SSSW frame according toEmbodiment 2 of this application;

FIG. 15 is a schematic structural diagram of a DMG parameters fieldaccording to Embodiment 2 of this application;

FIG. 16 is a flowchart of still another information transmission methodaccording to Embodiment 2 of this application;

FIG. 17 is a flowchart of an information transmission method accordingto Embodiment 3 of this application;

FIG. 18 is a flowchart of another information transmission methodaccording to Embodiment 3 of this application;

FIG. 19 is a schematic structural diagram of a DMG operation elementaccording to Embodiment 3 of this application;

FIG. 20 is a schematic structural diagram of a secondary-channel A-BFTelement according to Embodiment 3 of this application;

FIG. 21 is a schematic structural diagram of a broadcast frame accordingto Embodiment 3 of this application;

FIG. 22 is a diagram of a correspondence between a time range and achannel according to Embodiment 3 of this application;

FIG. 23 is a flowchart of still another information transmission methodaccording to Embodiment 3 of this application;

FIG. 24 is a schematic structural diagram of an A-BFT period accordingto Embodiment 3 of this application;

FIG. 25 is a flowchart of yet another information transmission methodaccording to Embodiment 3 of this application;

FIG. 26 is a schematic diagram of a message between a PCP/AP and astation in yet another information transmission method according toEmbodiment 3 of this application;

FIG. 27 is a schematic diagram of another message between an AP and astation in yet another information transmission method according toEmbodiment 3 of this application;

FIG. 28 is a flowchart of still another information transmission methodaccording to Embodiment 3 of this application;

FIG. 29 is a diagram of a correspondence between a quantity ofto-be-accessed user equipments and a quantity of SSW frames that can besent according to Embodiment 3 of this application;

FIG. 30 is a diagram of a correspondence between a quantity ofto-be-accessed user equipments and a quantity of user equipments thatcan actually access a network device according to Embodiment 3 of thisapplication;

FIG. 31 is a schematic structural diagram of a network device accordingto Embodiment 4 of this application; and

FIG. 32 is a schematic structural diagram of user equipment according toEmbodiment 4 of this application.

DESCRIPTION OF EMBODIMENTS

An information transmission method, a network device, and user equipmentthat are provided in embodiments of this application are applicable to aWLAN system, and in particular, to a WLAN system in the 802.11adstandard, that in the 802.11ay standard, and those in follow-up improvedstandards of the 802.11ad standard and the 802.11ay standard. Theinformation transmission method is applicable to a network scenario withuser equipments of multiple access types. FIG. 1 is a schematicstructural diagram of a network system applicable to the embodiments ofthis application. As shown in FIG. 1, the network system to which theinformation transmission method is applicable may include, for example,a network device, at least one directional multi-gigabit (DMG) userequipment, and at least one enhanced directional multi-gigabit (EDMG)user equipment. The DMG user equipment and the EDMG user equipment inFIG. 1 each may be user equipment of an access type. The network devicemay be, for example, a personal basic service set control point(PCP)/access point (AP). The user equipment may be a station (STA). TheDMG user equipment in FIG. 1 may be a DMG station, that is, a stationcorresponding to the 802.11ad standard, and the EDMG user equipment maybe an EDMG station, that is, a station corresponding to the 802.11aystandard.

By performing the information transmission method provided in thisapplication, the network device may send a frame that includes multiplepieces of duration information of A-BFT, so that each of the userequipments of multiple access types can determine a duration rangeaccording to duration information corresponding to the user equipment ofan access type, randomly select a timeslot from the duration range, andsend a corresponding frame to the network device in the randomlyselected timeslot. Therefore, the network device may implementbeamforming training of the user equipments of multiple access types inthe same A-BFT, so as to improve beamforming training efficiency andimprove a network throughput. User equipments of different access typesmay be user equipments in different communications standards. It shouldbe noted that the following methods in this application may beillustrated by using a solution in which two pieces of durationinformation are included. However, this is not limited in thisapplication.

Embodiment 1 of this application provides an information transmissionmethod. FIG. 2 is a flowchart of the information transmission methodaccording to Embodiment 1 of this application. As shown in FIG. 2, themethod may include the following steps.

S201. A network device sends a broadcast frame, where the broadcastframe includes first duration information and second durationinformation that are of A-BFT.

The first duration information is used by a first user equipment todetermine a first time range, so that the first user equipment randomlyselects a timeslot from the first time range. The second durationinformation is used by a second user equipment to determine a secondtime range, so that the second user equipment randomly selects atimeslot from the second time range.

The broadcast frame may be, for example, a beacon frame. The networkdevice may send the broadcast frame, for example, in a broadcast ormulticast manner, so that multiple user equipments that include thefirst user equipment and the second user equipment receive the broadcastframe.

The first user equipment and the second user equipment may berespectively user equipments of different access types, such as userequipments in different communications standards. The first userequipment may be, for example, a station corresponding to the 802.11adstandard that is also referred to as a DMG station. The second userequipment may be, for example, a station corresponding to the 802.11aystandard that may also be referred to as an EDMG station.

S202. First user equipment determines a first time range according tothe first duration information, and randomly selects a timeslot from thefirst time range.

If the first user equipment is a DMG station, the first durationinformation may be DMG duration information, and the first time rangemay be a DMG time range. The first user equipment randomly selects thetimeslot from the first time range. Therefore, the first time range mayalso be referred to as a contention range of the DMG station.

S203. Second user equipment determines a second time range according tothe second duration information, and randomly selects a timeslot fromthe second time range.

If the second user equipment is an EDMG station, the second durationinformation may be EDMG duration information, and the second time rangemay be an EDMG time range. The second user equipment randomly selectsthe timeslot from the second time range. Therefore, the second timerange may also be referred to as a contention range of the EDMG station.

Both the first duration information and the second duration informationare duration information of the A-BFT. Therefore, the first time rangeand the second time range may be two time ranges of the A-BFT. In theA-BFT, the first time range and the second time range may have nooverlapped time, or may have a partially-overlapped time. This is notlimited in this application.

S204. The first user equipment sends a first-type frame to the networkdevice in the timeslot randomly selected from the first time range.

In the timeslot randomly selected from the first time range, the firstuser equipment may further receive a feedback frame that iscorresponding to the first-type frame and sent by the network deviceafter receiving the first-type frame. The first-type frame may be, forexample, an SSW frame. The first user equipment sends the first-typeframe to the network device in the timeslot randomly selected from thefirst time range, so that the network device may implement beamformingtraining of the first user equipment in the first time range of theA-BFT.

S205. The second user equipment sends a second-type frame to the networkdevice in the timeslot randomly selected from the second time range.

In the timeslot randomly selected from the second time range, the seconduser equipment may further receive a feedback frame that iscorresponding to the second-type frame and sent by the network deviceafter receiving the second-type frame. The first-type frame may be of asame type as the second-type frame. The second-type frame may be, forexample, an SSW frame, or may be a frame of another type. The seconduser equipment sends the second-type frame to the network device in thetimeslot randomly selected from the second time range, so that thenetwork device may implement beamforming training of the second userequipment in the second time range of the A-BFT. It can be learned fromthe above that, according to the information transmission methoddescribed in Embodiment 1 of this application, the network device mayimplement beamforming training of user equipments of multiple accesstypes in same A-BFT, so as to improve beamforming training efficiencyand improve a network throughput.

It should be noted that, there is no absolute sequence between S202 andS203, and S202 and S203 may be successively performed, or may besimultaneously performed. There is no absolute sequence between S204 andS205, and S204 and S205 may be successively performed, or may besimultaneously performed. This is not limited in this application.

According to the information transmission method provided in Embodiment1 of this application, the network device sends the broadcast frame thatincludes the first duration information and the second durationinformation that are of the A-BFT, so that the first user equipment candetermine the first time range according to the first durationinformation, and randomly select the timeslot from the first time range,so as to send the first-type frame in the timeslot randomly selectedfrom the first time range; and the second user equipment can determinethe second time range according to the second duration information, andrandomly select the timeslot from the second time range, so as to sendthe second-type frame in the timeslot randomly selected from the secondtime range. Therefore, the network device may implement beamformingtraining of the user equipments of multiple access types in the sameA-BFT, so as to improve the beamforming training efficiency and improvethe network throughput.

Optionally, the first duration information may include duration of thefirst time range. Embodiment 2 of this application further provides aninformation transmission method. FIG. 3 is a flowchart in which firstuser equipment determines a first time range in the informationtransmission method according to Embodiment 2 of this application. Asshown in FIG. 3, in the information transmission method, S202 in whichfirst user equipment determines a first time range according to thefirst duration information may include the following steps:

S301. The first user equipment determines an end time of the first timerange according to a preset start time and the duration of the firsttime range.

S302. The first user equipment determines the first time range accordingto the preset start time and the end time of the first time range.

Specifically, the first user equipment may determine the end time of thefirst time range according to a sum of the preset start time and theduration of the first time range. After a start time and the end timethat are of the first time range are determined, the first time range isdetermined. The first time range is a time period from the start time ofthe first time range to the end time of the first time range.

For example, FIG. 4 is a schematic structural diagram of a BI accordingto Embodiment 2 of this application. As shown in FIG. 4, the BI mayinclude a beacon transmission interval (BTI), an A-BFT period, anannouncement transmission interval (ATI), and a data transfer interval(DTI). If the A-BFT period includes eight timeslots, and the presetstart time is 0, the start time of the first time range is a timeslot 0in the A-BFT period. If the duration of the first time range is 2, theend time of the first time range may be a timeslot 2 in the A-BFTperiod. In this case, the first time range may be three timeslots fromthe timeslot 0 to the timeslot 2 shown in FIG. 4, and may be representedas [timeslot 0, timeslot 2].

Optionally, the second duration information may include duration of thesecond time range. Embodiment 2 of this application further provides aninformation transmission method. FIG. 5 is a flowchart in which seconduser equipment determines a second time range in the informationtransmission method according to Embodiment 2 of this application. Asshown in FIG. 5, S203 in which second user equipment determines a secondtime range according to the second duration information may include thefollowing steps.

S501. The second user equipment determines a start time of the secondtime range according to the duration of the first time range.

Specifically, the second user equipment may determine the end time ofthe first time range according to the duration of the first time rangeand the preset start time, so as to determine the start time of thesecond time range according to the end time of the first time range.

S502. The second user equipment determines an end time of the secondtime range according to the start time of the second time range and theduration of the second time range.

The second user equipment may determine the end time of the second timerange according to a sum of the start time of the second time range andthe duration of the second time range.

S503. The second user equipment determines the second time rangeaccording to the start time of the second time range and the end time ofthe second time range.

After the start time and the end time that are of the second time rangeare determined, the second time range is determined. The second timerange is a time period from the start time of the second time range tothe end time of the second time range.

For example, FIG. 6 is a schematic structural diagram of another BIaccording to Embodiment 2 of this application. If the duration of thefirst time range is 2, the preset start time is 0, and the start time ofthe first time range is a timeslot 0 shown in FIG. 6, the end time ofthe first time range may be a timeslot 2 shown in FIG. 6. For example,the second user equipment may obtain a start time 3 of the second timerange by performing an operation of increasing the end time of the firsttime range by 1. In this case, the start time of the second time rangemay be a timeslot 3 shown in FIG. 6. If the duration of the second timerange is 4, that is, if the second time range may include fivetimeslots, the end time of the second time range is a timeslot 7. Inthis case, the second time range may be five timeslots from the timeslot3 to the timeslot 7 shown in FIG. 6, and the second time range may berepresented as [timeslot 3, timeslot 7].

Alternatively, in the information transmission method, the secondduration information may include duration of the second time range. FIG.7 is another schematic structural diagram in which second user equipmentdetermines a second time range in the information transmission methodaccording to Embodiment 2 of this application. As shown in FIG. 7, S203in which second user equipment determines a second time range accordingto the second duration information may include the following steps.

S701. The second user equipment determines an end time of the secondtime range according to the preset start time and the duration of thesecond time range.

In the information transmission method shown in FIG. 7, the second userequipment may use the preset start time as a start time of the secondtime range.

S702. The second user equipment determines the second time rangeaccording to the preset start time and the end time of the second timerange.

If the start time of the second time range is the preset start time, thesecond time range is a time period from the preset start time to the endtime of the second time range.

For example, FIG. 8 is a schematic structural diagram of still anotherBI according to Embodiment 2 of this application. If the preset starttime is 0, the start time of the second time range is a timeslot 0 shownin FIG. 8. If the duration of the second time range is 7, that is, ifthe second time range may include eight timeslots, the end time of thesecond time range is a timeslot 7. In this case, the second time rangemay be eight timeslots from the timeslot 0 to the timeslot 7 shown inFIG. 8, and the second time range may be represented as [timeslot 0,timeslot 7].

An access priority of the second user equipment may be higher than anaccess priority of the first user equipment. Therefore, in theinformation transmission method, the first time range and the secondtime range may have a partially-overlapped time, and the duration of thesecond time range may be greater than the duration of the first timerange, so that a time selection range of the second user equipment isgreater than a time selection range of the first user equipment, therebyeffectively reducing a probability of an access timeslot conflict of thesecond user equipment, and improving timeslot resource utilization.

It should be noted that the A-BFT period is described in the foregoingembodiments by using eight timeslots as an example. However,alternatively, the A-BFT period may include another quantity oftimeslots, for example, 16 timeslots. The broadcast frame may be, forexample, a beacon frame. The network device may further send a broadcastframe before S201 in which a network device sends a broadcast frame. Thepreviously sent broadcast frame may include ATI duration information.The first user equipment and the second user equipment may determine astart time and duration that are of an ATI according to the ATI durationinformation. The ATI duration information may be located in a start timefield and an ATI duration field in a next DMG ATI element in thepreviously sent broadcast frame. Because the A-BFT period is prior tothe ATI, the method may be as follows: An end time of the A-BFT periodis determined by allocating the start time of the ATI, so as to prolongduration of the A-BFT period. In this way, the duration of the A-BFTperiod may be greater than the eight timeslots shown in FIG. 4, FIG. 6,and FIG. 8, so that the first user equipment and the second userequipment can have larger time selection ranges to randomly selecttimeslots, so as to contend for access.

FIG. 9 is a schematic structural diagram of a next DMG ATI elementaccording to Embodiment 2 of this application. As shown in FIG. 9, thenext DMG ATI element may include a 1-byte element identifier (ElementID) field, a 1-byte length field, a 4-byte start time field, and 2-byteATI duration field.

If a BI does not include an ATI, the BI may include a DTI. In themethod, alternatively, a start time and duration that are of the DTI maybe determined according to DTI duration information included in abroadcast frame transmitted in a BTI in the BI. The DTI durationinformation may be located in any allocation field in an extendedschedule element in the broadcast frame. Each allocation field mayinclude an allocation start time and allocation duration. Because theA-BFT period is prior to the DTI, the method may be as follows: An endtime of the A-BFT period is determined by allocating the start time ofthe DTI, so as to prolong duration of the A-BFT period. In this way, theduration of the A-BFT period may be greater than the eight timeslotsshown in FIG. 4, FIG. 6, and FIG. 8, so that the first user equipmentand the second user equipment can have larger time selection ranges torandomly select timeslots, so as to contend for access.

FIG. 10 is a schematic structural diagram of an extended scheduleelement according to Embodiment 2 of this application. As shown in FIG.10, the extended schedule element may include a 1-byte elementidentifier, a 1-byte length, and at least one allocation field. Eachallocation field includes 15 bytes. With reference to FIG. 10, eachallocation field may include a 2-byte allocation control field, a 2-bytebeamforming control field, a 1-byte source association identifier(Source Association IDentity, Source AID) field, a 1-byte destinationassociation identifier (Destination AID) field, a 4-byte allocationstart field, a 2-byte allocation block duration field, a 1-byte numberof blocks field, and a 2-byte allocation block period field.

Optionally, if the broadcast frame is a beacon frame, the duration ofthe first time range may be located in an A-BFT length field of a BIcontrol field in the broadcast frame. The duration of the second timerange may be located in any one of the following locations in thebroadcast frame: at least one bit in the BI control field except theA-BFT length field, or a preset field or information element of a datapayload field. The preset field or information element includes at leastone bit.

For example, FIG. 11 is a schematic structural diagram of a BI controlfield according to Embodiment 2 of this application. As shown in FIG.11, the BI control field may include a 1-bit clustering control presentfield, a 1-bit discovery mode field, a 4-bit next beacon frame field, a1-bit ATI present field, a 3-bit A-BFT length field, a 4-bit frame ofsector sweep (FSS) field, a 1-bit is responder transmit sector sweep (IsResponder TXSS) field, a 4-bit next A-BFT field, a 1-bit fragmentedtransmit sector sweep (Fragmented TXSS) field, a 7-bit transmit sectorsweep span (TXSS Span) field, a 4-bit N BIs A-BFT field, a 6-bit A-BFTcount field, a 6-bit N A-BFT in an antenna interface (N A-BFT in Ant)field, a 1-bit basic service set control point association ready(Personal Basic Service Set Control Point Association Ready, or PCPAssociation Ready) field, and a 4-bit reserved field.

The duration of the first time range may be located in, for example, theA-BFT length field in FIG. 11, that is, in a bit 7 (B7) to a bit 9 (B9).The duration of the second time range may be located in, for example,the reserved field in the BI control field except the A-BFT length fieldin FIG. 11, that is, at least one of a bit 44 (B44) to a bit 47 (B47),such as at least one of B44, B45, B46, or B47. Alternatively, theduration of the second time range may be located in at least one bit inanother field in the BI control field except the A-BFT length field inFIG. 11.

Optionally, in the information transmission method, the second durationinformation includes indication information of the end time of thesecond time range. The start time of the second time range may bedetermined according to the duration of the first time range. The endtime of the second time range is determined according to the indicationinformation of the end time of the second time range.

For example, FIG. 11A is a schematic structural diagram of yet anotherBI according to Embodiment 2 of the present application. FIG. 11B is aschematic structural diagram of still yet another BI according toEmbodiment 2 of the present application. If the preset start time is 0,and the duration of the first time range is 3, the first time rangeincludes four timeslots from a timeslot 0 to a timeslot 3 shown in FIG.11A and FIG. 11B, and may be represented as [timeslot 0, timeslot 3].The start time of the second time range may be a timeslot 4. Theindication information of the end time of the second time range may belocated in, for example, at least one of B44, B45, B46, or B47 in FIG.11.

In a possible implementation, the indication information of the end timeof the second time range may be located in, for example, B44, B45, B46,and B47 in FIG. 11. If (B44 B45 B46 B47)=0000, it may be determined thatthe BI has no duration corresponding to the second user equipment, thatis, the second time range is 0, and the second user equipment does notneed to perform beamforming training in the BI. If (B44 B45 B46B47)=1000, it may be determined, according to preset duration andduration that is determined according to the indication information ofthe end time of the second time range, that the end time of the secondtime range is: preset duration+(B44 B45 B46 B47)−1. If the presetduration is 8, the end time of the second time range is a timeslot 15.In this case, the second time range may be [timeslot 4, timeslot 15]shown in FIG. 11A. In the method, the second time range is determinedaccording to the preset duration and the duration that is determinedaccording to the indication information of the end time of the secondtime range, so that the second time range may be longer, and the secondtime range may include more timeslots. It should be noted that in themethod, the indication information of the end time of the second timerange may be located in some of B44, B45, B46, and B47 in FIG. 11, andbe unnecessarily located in all of B44, B45, B46, and B47.

In another possible implementation, the indication information of theend time of the second time range may be located in, for example, B45and B46 in FIG. 11. If (B45 B46)=00, the BI has no durationcorresponding to the second user equipment, that is, the second timerange is 0, and the second user equipment does not need to performbeamforming training in the BI. If (B45 B46)=01, duration correspondingto the indication information of the end time of the second time rangeis 4. If (B45 B46)=10, duration corresponding to the indicationinformation of the end time of the second time range is 8. If (B45B46)=11, duration corresponding to the indication information of the endtime of the second time range is 16. If (B45 B46)=10, the second userequipment may determine, according to preset duration and the durationthat is corresponding to the indication information of the end time ofthe second time range, that the end time of the second time range is:preset duration+(B45 B46)−1. If the preset duration is 8, the end timeof the second time range is a timeslot 15. In this case, the second timerange may be [timeslot 4, timeslot 15] shown in FIG. 11A. It should benoted that in the method, the indication information of the end time ofthe second time range may be located in another bit in B44, B45, B46,and B47 in FIG. 11, and be unnecessarily located in the bits B45 andB46. In addition, the preset duration may also be another value such as6 or 7.

In still another possible implementation, the indication information ofthe end time of the second time range may be located in, for example,B45 and B46 in FIG. 11. If (B45 B46)=00, the BI has no durationcorresponding to the second user equipment, that is, the second timerange is 0, and the second user equipment does not need to performbeamforming training in the BI. If (B45 B46)=01, duration correspondingto the indication information of the end time of the second time rangeis 4. If (B45 B46)=10, duration corresponding to the indicationinformation of the end time of the second time range is 8. If (B45B46)=11, duration corresponding to the indication information of the endtime of the second time range is 16. If (B45 B46)=10, the second userequipment may determine, according to the start time of the second timerange and the duration that is corresponding to the indicationinformation of the end time of the second time range, that the end timeof the second time range is: start time of the second time range+(B45B46)−1. If the start time of the second time range is 4, the end time ofthe second time range is a timeslot 11. In this case, the second timerange may be [timeslot 4, timeslot 11] shown in FIG. 11B. It should benoted that in the method, the indication information of the end time ofthe second time range may be located in another bit in B44, B45, B46,and B47 in FIG. 11, and be unnecessarily located in the bits B45 andB46.

It should be noted that in the method, the A-BFT length field indicatesthe duration of the first time range. If the first user equipment is aDMG station, the duration that is of the first time range and indicatedby the A-BFT length field is duration for the DMG station. If bits of afield in which the duration of the first time range is located, forexample, (B7 B8 B9)=000, the first time range may include one timeslot,that is, a timeslot 0. Optionally, in the method, the network device mayfurther indicate, by using the next A-BFT field in the BI control fieldin the broadcast frame, whether the first user equipment needs toperform beamforming training. The network device may indicate, forexample, by making a value of the next A-BFT field greater than 0, thatthe first user equipment does not need to perform beamforming training,so that when the bits of the field in which the duration of the firsttime range is located, for example, (B7 B8 B9)=000, the second userequipment may determine, according to an indication that the value ofthe next A-BFT field is greater than 0, that the preset start time suchas the timeslot 0 is the start time of the second time range, andaccordingly, in a BI, only the second user equipment performsbeamforming training, and the first user equipment does not performbeamforming training. The value of the next A-BFT field may be, forexample, a value corresponding to the bits from B15 to B18 shown in FIG.11.

FIG. 12 is a schematic structural diagram of a broadcast frame accordingto Embodiment 2 of this application. As shown in FIG. 12, the broadcastframe may include a 2-byte frame control field, a 2-byte duration field,a 6-byte basic service set identity (BSSID) field, a data payload fieldof a non-fixed quantity of bytes, and a 4-byte frame check sequence(FCS) field. The data payload field may also be referred to as a bodyfield of the broadcast frame. The data payload field may includemultiple information elements. In the multiple information elements, asequence number 1 represents a timestamp element, a sequence number 2represents a sector sweep element, an element sequence number 3represents a BI element, a sequence number 4 represents a BI controlelement, a sequence number 14 represents a multi-band element, and thelike. The data payload field may include a newly added field orinformation element, for example, an information element with a sequencenumber 20. The newly added field or information element may be, forexample, an E-DMG A-BFT allocation element. As shown in FIG. 12, theinformation element with a sequence number 20 may include, for example,an 8-bit element identifier field, an 8-bit length field, a 3-bit A-BFTlength for an EDMG station (A-BFT length for EDMG STA) field, and a5-bit reserved field. Alternatively, the duration of the second timerange may be located in the A-BFT length for an EDMG station field inthe information element with a sequence number 20 in the data payloadfield shown in FIG. 12.

Optionally, the broadcast frame may further include frame typeindication information. FIG. 13 is a flowchart of another informationtransmission method according to Embodiment 2 of this application. Asshown in FIG. 13, optionally, before S205 in which the second userequipment sends a second-type frame to the network device in thetimeslot randomly selected from the second time range, the method mayfurther include the following step:

S1301. The second user equipment determines a frame type according tothe frame type indication information.

S205 in which the second user equipment sends a second-type frame to thenetwork device in the timeslot randomly selected from the second timerange may include the following step:

S1302. The second user equipment sends, to the network device in thetimeslot randomly selected from the second time range, the second-typeframe corresponding to the frame type, where transmission duration offrames corresponding to different frame types is different.

Optionally, the second-type frame is an SSW frame or a short sectorsweep (SSSW) frame. Transmission duration of the SSW frame is greaterthan transmission duration of the SSSW frame.

Specifically, the SSW frame may be a frame corresponding to the 802.11adstandard. A frame corresponding to the 802.11ay standard may be an SSWframe, or may be an SSSW frame.

If the second-type frame is the SSSW frame, because the transmissionduration of the SSSW frame is less than the transmission duration of theSSW frame, the second user equipment may transmit more second-typeframes in the timeslot randomly selected from the second time range, sothat the network device can implement more accurate beamforming trainingof the second user equipment.

For example, Embodiment 2 of this application may further provide anSSSW frame. FIG. 14 is a schematic structural diagram of an SSSW frameaccording to Embodiment 2 of this application. As shown in FIG. 14, theSSSW frame may include a 2-bit packet type field, a 16-bit addressfield, an 11-bit down counter field, a 2-bit radio frequency chainidentity (RF Chain ID) field, an 11-bit short sector sweep feedback(SSSW Feedback) field, a 1-bit direction field, a 1-bit reserved field,and a 4-bit frame check sequence field.

Optionally, if the broadcast frame is a beacon frame, the frame typeindication information is located in at least one reserved bit in a DMGparameters field of the broadcast frame.

FIG. 15 is a schematic structural diagram of a DMG parameters fieldaccording to Embodiment 2 of this application. As shown in FIG. 15, theDMG parameters field may include a 2-bit basic service set type (BSSType) field, a 1-bit contention-based access period only (CBAP Only)field, a 1-bit contention-based access period source (CBAP Source)field, a 1-bit directional multi-gigabit privacy (DMG Privacy) field, a1-bit ECPAC policy enforced field, and a 2-bit reserved field.

In the information transmission method, the frame type indicationinformation may be located in at least one reserved bit in the DMGparameters field shown in FIG. 15, that is, at least one of a bit 6 or abit 7 in FIG. 15. The second user equipment may determine a frame typeof the second-type frame according to the frame type indicationinformation, so as to determine whether the second-type frame is an SSWframe or an SSSW frame.

Optionally, the broadcast frame may further include frame quantityindication information. FIG. 16 is a flowchart of still anotherinformation transmission method according to Embodiment 2 of thisapplication. As shown in FIG. 16, optionally, before S205 in which thesecond user equipment sends a second-type frame to the network device inthe timeslot randomly selected from the second time range, the methodmay further include the following step:

S1601. The second user equipment determines a quantity of to-be-sentframes according to the frame quantity indication information.

S205 in which the second user equipment sends a second-type frame to thenetwork device in the timeslot randomly selected from the second timerange may include the following step:

S1602. The second user equipment successively sends the frame quantityof the second-type frames to the network device in the timeslot randomlyselected from the second time range.

Optionally, before S204 in which the first user equipment sends afirst-type frame to the network device in the timeslot randomly selectedfrom the first time range, the method may further include:

-   -   determining, by the first user equipment, a quantity of        to-be-sent frames according to the frame quantity indication        information.

S204 in which the first user equipment sends a first-type frame to thenetwork device in the timeslot randomly selected from the first timerange may include:

-   -   successively sending, by the first user equipment, the frame        quantity of the first-type frames to the network device in the        timeslot randomly selected from the first time range.

That is, the frame quantity indication information may be used toindicate a quantity of the second-type frames to be sent by the seconduser equipment, or may be used to indicate a quantity of the first-typeframes to be sent by the first user equipment.

Optionally, if the broadcast frame is a beacon frame, the frame quantityindication information may be located in the FSS field in the BI controlfield of the broadcast frame shown in FIG. 11, or may be located in anenhanced frame of sector sweep (EFSS) field in the broadcast frame. Ifthe second-type frame is an SSW frame, the frame quantity indicationinformation may be a quantity of SSW frames to be sent by the seconduser equipment, and the frame quantity indication information may belocated in the FSS field in the broadcast frame. If the second-typeframe is an SSSW frame, the frame quantity indication information is aquantity of SSSW frames to be sent by the second user equipment, and theframe quantity indication information may be located in the EFSS fieldin the broadcast frame. The EFSS field may be a reserved field in thebroadcast frame, or may be a newly added field in the broadcast frame.

Based on the foregoing methods, Embodiment 3 of this application furtherprovides an information transmission method. Optionally, the broadcastframe may further include usage indication information of at least onechannel. FIG. 17 is a flowchart of the information transmission methodaccording to Embodiment 3 of this application. As shown in FIG. 17, S205in which the second user equipment sends a second-type frame to thenetwork device in the timeslot randomly selected from the second timerange includes the following steps:

S1701. The second user equipment determines, according to the usageindication information of the at least one channel, whether the at leastone channel is available; and selects an available channel from the atleast one channel.

S1702. The second user equipment sends the second-type frame to thenetwork device through the available channel in the timeslot randomlyselected from the second time range.

The available channel may be a main channel, or may be a secondarychannel.

Optionally, S1702 in which the second user equipment sends thesecond-type frame to the network device through the available channel inthe timeslot randomly selected from the second time range may include:

-   -   if the available channel is a main channel, sending, by the        second user equipment, the second-type frame to the network        device through the available channel in the timeslot randomly        selected from the second time range.

For example, if the A-BFT period includes eight timeslots from atimeslot 0 to a timeslot 7, the first time range may be three timeslotsfrom the timeslot 0 to the timeslot 2 shown in FIG. 4, and the secondtime range includes five timeslots from the timeslot 3 to the timeslot 7shown in FIG. 6. If the available channel selected by the second userequipment is a main channel, the second user equipment may send thesecond-type frame to the network device through the main channel in atimeslot selected from the timeslot 3 to the timeslot 7.

Optionally, the broadcast frame may further include usage indicationinformation of at least one channel and duration informationcorresponding to each channel. FIG. 18 is a flowchart of anotherinformation transmission method according to Embodiment 3 of thisapplication. As shown in FIG. 18, the method may further include thefollowing steps.

S1801. The second user equipment determines, according to the usageindication information of the at least one channel, whether the at leastone channel is available; and selects an available channel from the atleast one channel.

S1802. If the available channel is a secondary channel, the second userequipment determines, according to duration information corresponding tothe available channel, a time range corresponding to the availablechannel.

Each channel has corresponding duration information. A time rangecorresponding to each channel may be determined according to theduration information corresponding to each channel. Time rangescorresponding to different secondary channels may be the same, or may bedifferent.

For example, if the available channel is a secondary channel, and thesecondary channel is a channel 2, the second user equipment maydetermine, according to duration information corresponding to thechannel 2 in the broadcast frame, a time range corresponding to thechannel 2.

S1803. The second user equipment randomly selects a timeslot from thetime range corresponding to the available channel.

S1804. The second user equipment sends the second-type frame through theavailable channel in the timeslot randomly selected from the time rangecorresponding to the available channel.

Optionally, the usage indication information of the at least one channeland/or the duration information corresponding to each channel are/islocated in any one of the following locations in the broadcast frame:

-   -   at least one reserved bit of a DMG operation information field        in a DMG operation element; or    -   a preset field or information element in a data payload field,        where the preset field or information element includes at least        one bit.

The following provides description by using instances. FIG. 19 is aschematic structural diagram of a DMG operation element according toEmbodiment 3 of this application. As shown in FIG. 19, the DMG operationelement may include a 1-byte element identifier field, a 1-byte lengthfield, a 2-byte DMG operation information field, and an 8-byte DMG basicservice set parameter configuration field.

The DMG operation information field may include a 1-bit time divisiondata transfer interval (TDDTI) field, a 1-bit pseudo-static allocationsfield, a 1-bit basic service set control point handover (Personal BasicService Set Control Point Handover, or PCP Handover) field, and a 13-bitreserved field.

The usage indication information of the at least one channel and/or theduration information corresponding to each channel may be located in,for example, at least one of B3 to B15 shown in FIG. 19 in the broadcastframe.

For example, there are currently four channels, that is, a channel 1, achannel 2, a channel 3, and a channel 4. The channel 1 may be a mainchannel. Usage indication information of the four channels may belocated in B3, B4, B5, and B6 in the reserved field shown in FIG. 19.Alternatively, the broadcast frame may include only usage indicationinformation of a secondary channel. In this case, usage indicationinformation of the three secondary channels may be located in B3, B4,and B5 in the reserved field shown in FIG. 19.

For the secondary channels in the four channels, that is, the channel 2,the channel 3, and the channel 4, duration information corresponding tothe channel 2 may be located in, for example, B6, B7, and B8 shown inFIG. 19; duration information corresponding to the channel 3 may belocated in, for example, B9, B10, and B11 shown in FIG. 19; and durationinformation corresponding to the channel 4 may be located in, forexample, B12, B13, and B14 shown in FIG. 19.

In another instance, the usage indication information of the at leastone channel and/or the duration information corresponding to eachchannel may be located in the preset field or information element in thedata payload field in the broadcast frame.

FIG. 20 is a schematic structural diagram of a secondary-channel A-BFTelement according to Embodiment 3 of this application. As shown in FIG.20, the secondary-channel A-BFT element may include an 8-bit elementidentifier field, an 8-bit length field, a 1-bit A-BFT for a channel 2(A-BFT for Secondary channel 2) field, a 1-bit A-BFT for a channel 3(A-BFT for Secondary channel 3) field, a 1-bit A-BFT for a channel 4(A-BFT for Secondary channel 4) field, and a 5-bit reserved field. Forexample, if a value of the A-BFT for a channel 2 field is 1, the channel2 may be an available channel for the second user equipment, and thesecond user equipment may send the second-type frame to the networkdevice on the channel 2 to implement beamforming training. If a value ofthe A-BFT for a channel 2 field is 0, the channel 2 is unavailable tothe second user equipment, and the second user equipment cannot send thesecond-type frame to the network device on the channel 2 to implementbeamforming training.

FIG. 21 is a schematic structural diagram of a broadcast frame accordingto Embodiment 3 of this application. As shown in FIG. 21, the broadcastframe may include a 2-byte frame control field, a 2-byte duration field,a 6-byte basic service set identity field, a data payload field of anon-fixed quantity of bytes, and a 4-byte frame check sequence field.The data payload field may also be referred to as a body field of thebroadcast frame. The data payload field may include multiple informationelements. The data payload field may include a newly added field orinformation element, for example, an information element with a sequencenumber 21. The newly added field or information element may be, forexample, a secondary-channel A-BFT allocation element. As shown in FIG.21, the information element with a sequence number 21 may include, forexample, an 8-bit element identifier field, an 8-bit length field, a3-bit A-BFT length for a channel 2 (A-BFT Length for Secondary channel2) field, a 3-bit A-BFT length for a channel 3 (A-BFT Length forSecondary channel 3) field, a 3-bit A-BFT length for a channel 4 (A-BFTLength for Secondary channel 4) field, and a 7-bit reserved field.

For the secondary channels in the four channels, that is, the channel 2,the channel 3, and the channel 4, duration information corresponding tothe channel 2 may be located in, for example, the A-BFT length for achannel 2 field shown in FIG. 21; duration information corresponding tothe channel 3 may be located in, for example, the A-BFT length for achannel 3 field shown in FIG. 21; and duration information correspondingto the channel 4 may be located in, for example, the A-BFT length for achannel 4 field shown in FIG. 21.

FIG. 22 is a diagram of a correspondence of time ranges corresponding tochannels according to Embodiment 3 of this application. As shown in FIG.22, if the available channel selected by the second user equipment is amain channel, that is, the channel 1, the second user equipment mayselect a timeslot from a timeslot 3 to a timeslot 7 shown in FIG. 22, soas to send the second-type frame to the network device through thechannel 1 in the selected timeslot. If the available channel selected bythe second user equipment is a secondary channel, such as the channel 2,the second user equipment may select a timeslot from the timeslot 0 to atimeslot 6 shown in FIG. 22, so as to send the second-type frame to thenetwork device through the channel 2 in the selected timeslot. If theavailable channel selected by the second user equipment is the channel3, the second user equipment may select a timeslot from the timeslot 0to a timeslot 7 shown in FIG. 22, so as to send the second-type frame tothe network device through the channel 3 in the selected timeslot. Ifthe available channel selected by the second user equipment is thechannel 4, the second user equipment may select a timeslot from thetimeslot 0 to a timeslot 5 shown in FIG. 22, so as to send thesecond-type frame to the network device through the channel 4 in theselected timeslot.

It should be noted that FIG. 19 to FIG. 22 are merely instances fordescription. Alternatively, the usage indication information of the atleast one channel and/or the duration information corresponding to eachchannel may be located in another location in the broadcast frame. Thisis not limited in this application.

Based on the foregoing methods, optionally, Embodiment 3 of thisapplication further provides an information transmission method. FIG. 23is a flowchart of still another information transmission methodaccording to Embodiment 3 of this application. As shown in FIG. 23, themethod is based on the foregoing embodiments. Before S205 in which thesecond user equipment sends a second-type frame to the network device inthe timeslot randomly selected from the second time range, the methodmay further include the following step:

S2301. The second user equipment randomly selects backoff duration inthe timeslot randomly selected from the second time range.

Step S205 in which the second user equipment sends a second-type frameto the network device in the timeslot randomly selected from the secondtime range may include the following step:

S2302. The second user equipment sends the second-type frame to thenetwork device after the backoff duration in the timeslot randomlyselected from the second time range.

The second user equipment randomly selects the timeslot from the secondtime range to implement first-time backoff, and randomly selects thebackoff duration in the timeslot randomly selected from the second timerange, to implement second-time backoff. After the second user equipmentselects the backoff duration, when the timeslot randomly selected by thesecond user equipment from the second time range arrives, the seconduser equipment does not instantly send the second-type frame, but startsa countdown timer corresponding to the backoff duration. When thecountdown timer corresponding to the backoff duration is 0, that is,after the backoff duration, the second user equipment may send thesecond-type frame. The second user equipment randomly selects thebackoff duration in the timeslot randomly selected from the second timerange. Therefore, even if another user equipment also selects the sametimeslot from the second time range, because each user equipment furtherrandomly selects backoff duration, a possibility that the randomlyselected backoff duration is different is relatively high. Therefore,user equipment with shorter backoff duration may preferentially send thesecond-type frame in the same timeslot, and user equipment with longerbackoff duration may not send the second-type frame, after the backoffduration, when detecting, by means of carrier sense or clear channelassessment (CCA), that a channel is busy, so as to avoid interferenceimposed on the user equipment that preferentially sends the second-typeframe, effectively reduce a collision within the timeslot, and improvetraining efficiency of the A-BFT.

For example, FIG. 24 is a schematic structural diagram of an A-BFTperiod according to Embodiment 3 of this application. As shown in FIG.24, the A-BFT period may include eight timeslots from a timeslot 0 to atimeslot 7. The first time range ranges from the timeslot 0 to thetimeslot 2, and the second time range ranges from the timeslot 3 to thetimeslot 7. If the timeslot randomly selected by the second userequipment from the second time range is the timeslot 3, the second userequipment randomly selects backoff duration in the timeslot 3, and maysend the second-type frame such as an SSW frame after the backoffduration.

Alternatively, Embodiment 3 of this application further provides aninformation transmission method. FIG. 25 is a flowchart of yet anotherinformation transmission method according to Embodiment 3 of thisapplication. As shown in FIG. 25, the method is based on the foregoingembodiments. Before S205 in which the second user equipment sends asecond-type frame to the network device in the timeslot randomlyselected from the second time range, the method may further include thefollowing step:

S2501. The second user equipment determines, according to an accesspriority of the second user equipment, backoff duration corresponding tothe access priority.

A higher access priority indicates shorter backoff duration. A loweraccess priority indicates longer backoff duration.

That is, in the information transmission method, the backoff durationmay be determined according to the access priority of the second userequipment, and be unnecessarily randomly selected.

S205 in which the second user equipment sends a second-type frame to thenetwork device in the timeslot randomly selected from the second timerange may include the following step:

S2502. The second user equipment sends the second-type frame to thenetwork device after the backoff duration in the timeslot randomlyselected from the second time range.

In a dense scenario, a probability of a timeslot conflict that occursduring the A-BFT period when multiple user equipments performbeamforming training is relatively high. To achieve an objective thatuser equipment that still cannot perform access after multiple trainingperiods quickly accesses the network device, to quickly completebeamforming training, thereby improving training timeliness, andimproving user experience, in the information transmission method, theaccess priority may be determined according to a quantity of accessfailures of the second user equipment. A larger quantity of accessfailures indicates a higher access priority, so that backoff durationfor the user equipment reduces as the quantity of access failuresincreases.

To reduce a timeslot conflict between user equipments, in theinformation transmission method, alternatively, the access priority maybe determined according to a quantity of access failures of the seconduser equipment. A larger quantity of access failures indicates a loweraccess priority, so that backoff duration for the user equipmentincreases as the quantity of access failures increases, and userequipments with different quantities of access failures accordingly havedifferent backoff duration, so as to effectively reduce the timeslotconflict.

To reduce a timeslot conflict between user equipments, in theinformation transmission method, a quantity of access failures of theuser equipment may be unrelated to backoff duration, that is, the accesspriority may be determined according to another parameter of the userequipment. Therefore, the backoff duration may remain unchanged as thequantity of access failures increases.

For example, if the network device is a PCP/AP, and the user equipmentis a station, the station may be an EDMG station, and a time rangecorresponding to the station may include eight timeslots from a timeslot0 to a timeslot 7. FIG. 26 is a schematic diagram of a message between aPCP/AP and a station in yet another information transmission methodaccording to Embodiment 3 of this application. As shown in FIG. 26, in afirst period, the PCP/AP may send a beacon frame in a BTI in a broadcastmanner. All of a station 1, a station 4, and a station 8 select atimeslot 0 in the time range, backoff duration selected by the station 1in the timeslot 0 may be less than backoff duration for the station 4and that for the station 8. Therefore, the station 1 may preferentiallysend an SSW frame, to preferentially perform access. A timeslot conflictoccurs between the station 4 and the station 8 in the timeslot 0.Consequently, both access of the station 4 and access of the station 8fail. In a second period, a timeslot selected by the station 4 in thetime range is a timeslot 0, and timeslots selected by the station 8 anda station 9 in the time range are a timeslot 1. The station 8 is userequipment whose access fails in the first period, and the station 9 isnew user equipment. Therefore, an access priority of the station 8 maybe higher than an access priority of the station 9. Backoff durationthat may be selected by the station 8 in the timeslot 1 may be less thanbackoff duration selected by the station 9 in the timeslot 1. Therefore,access of the station 8 may succeed in the timeslot 1, and access of thestation 9 may fail in the timeslot 1. Only the station 4 sends an SSWframe in the timeslot 0. Therefore, access of the station 4 succeeds inthe timeslot 0. As shown above, a period is a BI.

Optionally, S2501 in which the second user equipment determines,according to an access priority of the second user equipment, backoffduration corresponding to the access priority may include the followingstep:

S2501 a. The second user equipment determines the access priorityaccording to a quantity of access failures of the second user equipment.

A larger quantity of access failures indicates a higher access priority.

Optionally, a larger quantity of access failures may indicate a loweraccess priority.

It should be noted that in the information transmission method shown inFIG. 25, the access priority is determined according to the quantity ofaccess failures. Alternatively, the second user equipment may determinethe access priority according to another parameter in addition to thequantity of access failures. Details are not described herein in thisapplication.

The following provides description by using two specific instances.

In an instance, if the second user equipment is new user equipment, thatis, if a quantity of access failures of the second user equipment is 0,the second user equipment may determine a backoff window according tothe following formula (1), so as to determine the backoff duration fromthe backoff window:

t ₁=2^(F) ^(max)   Formula (1),

where t₁ is the backoff window determined by the second user equipment,and F_(max) is a preset maximum quantity of access failures. F_(max) maybe less than dot1RSSRetryLimit, where dot11RSSRetryLimit may be, forexample, a responder sector sweep (RSS) retry limit in the 802.11standard. If the second user equipment is new user equipment, thebackoff duration time₁ for the second user equipment may fall within[0,t₁], that is time₁˜U[0,t₁].

If the second user equipment is user equipment whose access fails, thatis, if a quantity of access failures of the second user equipment isgreater than 0, the second user equipment may determine a backoff windowaccording to the following formula (2):

t ₂=2^(F) ^(max) ^(−F)  Formula (2),

where t₂ is the backoff window determined by the second user equipment,F is the quantity of access failures of the second user equipment, and Fmay be determined according to a value of an attempt failure countercorresponding to the second user equipment. The attempt failure countermay be, for example, a FailedRSSattempts counter. F may be less than orequal to F_(max), that is, F may be a minimum value between F andF_(max), and this is represented as F=min{F,F_(max)}. If the second userequipment is user equipment whose access fails, backoff duration time₂for the second user equipment may fall within [0,t₂], that is,time₂˜U[0,t₂].

In the foregoing instance, if the quantity of access failures is lessthan or equal to the preset maximum quantity of access failures, thebackoff duration for the second user equipment may reduce as thequantity of access failures increases. If the quantity of accessfailures is greater than the preset maximum quantity of access failures,the backoff duration for the second user equipment is equal to backoffduration corresponding to the maximum quantity of access failures, anddoes not continue to reduce as the quantity of failures increases.

In another instance, if the network device is an AP, and the userequipment is a station, the station may be an EDMG station, and a timerange corresponding to the station may include eight timeslots from atimeslot 0 to a timeslot 7. FIG. 27 is a schematic diagram of anothermessage between an AP and a station in yet another informationtransmission method according to Embodiment 3 of this application. Asshown in FIG. 27, in a first period, the AP may broadcast a beacon framein a BTI. A station 1 and a station 2 select a timeslot 0 in the timerange. Backoff duration selected by the station 1 in the timeslot 0 maybe less than backoff duration selected by the station 2 in the timeslot0. Therefore, the backoff duration for the station 1 may preferentiallydecrease to 0. In this case, the station 1 may preferentially send anSSW frame, to preferentially perform access. The station 2 maintains achannel sensing state in the backoff duration. When the station 1 sendsthe SSW frame, the station 2 detects that a channel is busy, the station2 does not send an SSW frame, and access of the station 2 fails. At thesame time, the station 2 may stop decreasing of the backoff duration forthe station 2. In a second period, if both the station 2 and a newstation 3 select a timeslot 0 in the time range, the station 2 startsdecreasing of the backoff duration for the station 2 again in thetimeslot 0, and sends the SSW frame when the backoff duration for thestation 2 decreases to 0. Backoff duration for the station 3, as newuser equipment, in the timeslot 0 may be greater than the backoffduration for the station 2 in the second period. Therefore, the station2 preferentially sends the SSW frame, to preferentially perform access.The station 3 maintains a channel sensing state in the backoff duration.When the station 2 sends the SSW frame, the station 3 detects that achannel is busy, the station 3 does not send an SSW frame, and access ofthe station 3 fails. At the same time, the station 3 may stop decreasingof the backoff duration for the station 3.

It should be noted that in the method instance, backoff durationselected by new user equipment in a timeslot selected by the new userequipment may be preset maximum backoff duration. That is, in the firstperiod in FIG. 27, the backoff duration selected by the station 1 andthe station 2 in the timeslot 0 may be the preset maximum backoffduration, and the backoff duration selected by the station 3 in thetimeslot 0 in the second period may be the preset maximum backoffduration.

To reduce a probability that a timeslot collision occurs betweendifferent user equipments in a same timeslot, the backoff duration inthe foregoing embodiment may gradually decrease as a quantity of accessfailures increases; or may be fixed backoff duration, that is, does notchange as a quantity of access failures increases; or the backoffduration may increase as a quantity of failures increases.

The instances are merely examples for description. This is not limitedin this application.

Embodiment 3 of this application may further provide an informationtransmission method. FIG. 28 is a flowchart of still another informationtransmission method according to Embodiment 3 of this application. Asshown in FIG. 28, before S201 in which a network device sends abroadcast frame, the method may further include the following step:

S2801. The network device determines whether a quantity ofto-be-accessed user equipments is greater than a preset quantity value.

S201 in which a network device sends a broadcast frame may include thefollowing step:

S2802. The network device sends the broadcast frame if the quantity ofuser equipments is greater than or equal to the preset quantity value.

That is, if the quantity of user equipments is greater than or equal tothe preset quantity value, the network device may send the broadcastframe that includes multiple pieces of duration information of theA-BFT, so as to perform the information transmission method in any oneof the foregoing embodiments. However, to avoid resource waste caused bybackoff duration, if the quantity of user equipments is less than thepreset quantity value, the network device may further send aconventional broadcast frame, that is, a broadcast frame that includesone piece of duration information of the A-BFT.

It should be noted that after at least one BI after startup, the networkdevice may determine, by performing S2801 of determining whether thequantity of to-be-accessed user equipments is greater than the presetquantity value, whether the user equipment is to perform a separatedA-BFT method. If the quantity of user equipments is greater than orequal to the preset quantity value, the network device determines thatthe user equipment may perform the separated A-BFT, so as to performS2802 in which the network device may send the broadcast frame thatincludes multiple pieces of duration information of the A-BFT. However,in the at least one BI after startup, the broadcast frame sent by thenetwork device may include only one piece of duration information of theA-BFT, that is, the user equipment does not perform the separated A-BFTsolution in the at least one BI.

Optionally, the broadcast frame may further include overload indicator(OI) information. The overload indicator information is located in anyone of the following locations: a reserved bit of a BI control field ofa frame control field, or a reserved bit of another field other than theBI control field.

FIG. 29 is a diagram of a correspondence between a quantity ofto-be-accessed user equipments and a quantity of SSW frames that can besent according to Embodiment 3 of this application. As shown in FIG. 29,if the quantity of to-be-accessed user equipments is greater than 5, aquantity of SSW frames that can be sent by each user equipment by usinga conventional A-BFT mechanism may be less than a quantity of SSW framesthat can be sent by using a two-time-backoff A-BFT mechanism. That is,if the quantity of to-be-accessed user equipments is greater than 5, thequantity of SSW frames that can be sent may be increased by using thetwo-time-backoff mechanism, and system performance is improved. If thequantity of to-be-accessed user equipments is less than 5, a quantity ofSSW frames that can be sent by each user equipment by using aconventional A-BFT mechanism may be greater than a quantity of SSWframes that can be sent by using a two-time-backoff A-BFT mechanism. Inthis way, SSW frame sending opportunity waste caused by backoff durationmay be effectively avoided.

FIG. 30 is a diagram of a correspondence between a quantity ofto-be-accessed user equipments and a quantity of user equipments thatcan actually access a network device according to Embodiment 3 of thisapplication. It can be learned from FIG. 30 that when the quantity ofto-be-accessed user equipments is relatively large, a quantity of userequipments that can perform access may be effectively increased by usingthe two-time-backoff A-BFT mechanism, and training efficiency isimproved.

It should be noted that, the conventional A-BFT mechanism in FIG. 29 andFIG. 30 may be, for example, a manner in which the broadcast frame sentby the network device may include one piece of duration information ofA-BFT, and each user equipment randomly selects a timeslot in an A-BFTperiod, so as to send an SSW frame in the selected timeslot. Thetwo-time-backoff A-BFT mechanism may be, for example, a manner in whichthe broadcast frame sent by the network device may include multiplepieces of duration information of A-BFT, and each user equipment selectsa timeslot from a corresponding time range, and selects backoff durationin the selected timeslot, so as to send an SSW frame after the backoffduration in the selected timeslot. In addition to two-time backoff, theinformation transmission method in this application may includemultiple-time backoff, that is, after selecting the backoff duration,the user equipment may further select backoff duration to send the SSWframe after the selected backoff duration, so as to implement themultiple-time backoff. The foregoing is only an instance fordescription. This is not limited in this application.

Embodiment 4 of this application may further provide a network device.FIG. 31 is a schematic structural diagram of the network deviceaccording to Embodiment 4 of this application. As shown in FIG. 31, thenetwork device 3100 may include a transmitter 3101 and a receiver 3102.

The transmitter 3101 is configured to send a broadcast frame. Thebroadcast frame includes first duration information and second durationinformation that are of A-BFT. The first duration information is used bya first user equipment to determine a first time range, so that thefirst user equipment randomly selects a timeslot from the first timerange. The second duration information is used by a second userequipment to determine a second time range, so that the second userequipment randomly selects a timeslot from the second time range.

The receiver 3102 is configured to: receive a first-type frame sent bythe first user equipment in the timeslot randomly selected from thefirst time range; and receive a second-type frame sent by the seconduser equipment in the timeslot randomly selected from the second timerange.

Optionally, the first duration information includes duration of thefirst time range. The duration of the first time range is used by thefirst user equipment to determine an end time of the first time rangeaccording to a preset start time and the duration of the first timerange, and determine the first time range according to the preset starttime and the end time of the first time range.

Optionally, the second duration information includes duration of thesecond time range. The duration of the first time range is further usedby the second user equipment to determine a start time of the secondtime range according to the duration of the first time range.

The duration of the second time range is used by the second userequipment to determine an end time of the second time range according tothe start time of the second time range and the duration of the secondtime range, and determine the second time range according to the starttime of the second time range and the end time of the second time range.

Optionally, the second duration information includes duration of thesecond time range.

The duration of the second time range is used by the second userequipment to determine an end time of the second time range according tothe preset start time and the duration of the second time range, anddetermine the second time range according to the preset start time andthe end time of the second time range.

Optionally, the broadcast frame further includes frame type indicationinformation. The frame type indication information is used by the seconduser equipment to determine a frame type.

The receiver 3102 is specifically configured to receive the second-typeframe that is corresponding to the frame type and sent by the seconduser equipment in the timeslot randomly selected from the second timerange. Transmission duration of frames corresponding to different frametypes is different.

Optionally, the broadcast frame further includes frame quantityindication information. The frame quantity indication information isused by the second user equipment to determine a frame quantity.

The receiver 3102 is specifically configured to receive the framequantity of the second-type frames successively sent by the second userequipment in the timeslot randomly selected from the second time range.

Optionally, the broadcast frame further includes usage indicationinformation of at least one channel. The usage indication information ofthe at least one channel is used by the second user equipment todetermine whether the at least one channel is available, so that thesecond user equipment selects an available channel from the at least onechannel.

The receiver 3102 is further specifically configured to receive thesecond-type frame sent by the second user equipment through theavailable channel in the timeslot randomly selected from the second timerange.

Optionally, the receiver 3102 is further specifically configured to: ifthe available channel is a main channel, receive the second-type framesent by the second user equipment through the available channel in thetimeslot randomly selected from the second time range.

Optionally, the broadcast frame further includes duration informationcorresponding to each channel. The duration information corresponding toeach channel is used by the second user equipment to determine a timerange corresponding to each channel, so that if the available channel isa secondary channel, the second user equipment randomly selects atimeslot from a time range corresponding to the available channel.

The receiver 3102 is further configured to receive the second-type framesent by the second user equipment through the available channel in thetimeslot randomly selected from the time range corresponding to theavailable channel.

Optionally, the second duration information is specifically used by thesecond user equipment to determine the second time range, so that thesecond user equipment randomly selects a timeslot from the second timerange, and randomly selects backoff duration in the randomly selectedtimeslot.

The receiver 3102 is specifically configured to receive the second-typeframe sent by the second user equipment after the backoff duration inthe timeslot randomly selected from the second time range.

Optionally, the backoff duration is determined by the second userequipment according to an access priority corresponding to the seconduser equipment. A higher access priority corresponding to the seconduser equipment indicates shorter backoff duration. A lower accesspriority corresponding to the second user equipment indicates longerbackoff duration.

Optionally, a larger quantity of access failures of the second userequipment indicates a higher access priority corresponding to the seconduser equipment.

The network device provided in Embodiment 4 of this application mayperform the information transmission method performed by the networkdevice in either Embodiment 1 or Embodiment 2. A beneficial effect ofEmbodiment 3 is similar to those of the foregoing embodiments. Detailsare not described herein again.

Embodiment 4 of this application further provides user equipment 3200.FIG. 32 is a schematic structural diagram of the user equipmentaccording to Embodiment 4 of this application. As shown in FIG. 32, theuser equipment 3200 is second user equipment. The user equipment 3200may include a receiver 3201, a processor 3202, and a transmitter 3203.The receiver 3201 is connected to the processor 3202. The processor 3202is connected to the transmitter 3203.

The receiver 3201 is configured to receive a broadcast frame sent by anetwork device. The broadcast frame includes first duration informationand second duration information that are of A-BFT. The first durationinformation is used by a first user equipment to determine a first timerange, so that the first user equipment randomly selects a timeslot fromthe first time range, so as to send a first-type frame to the networkdevice in the timeslot randomly selected from the first time range.

The processor 3202 is configured to determine a second time rangeaccording to the second duration information, and randomly select atimeslot from the second time range.

The transmitter 3203 is configured to send a second-type frame to thenetwork device in the timeslot randomly selected from the second timerange.

Optionally, the first duration information includes duration of thefirst time range, and the second duration information includes durationof the second time range.

The processor 3202 is specifically configured to: determine a start timeof the second time range according to the duration of the first timerange; determine an end time of the second time range according to thestart time of the second time range and the duration of the second timerange; and determine the second time range according to the start timeof the second time range and the end time of the second time range.

Optionally, the second duration information includes duration of thesecond time range.

The processor 3202 is further specifically configured to: determine anend time of the second time range according to a preset start time andthe duration of the second time range, where the preset start time is apreset start time of the first time range; and determine the second timerange according to the preset start time and the end time of the secondtime range.

Optionally, the broadcast frame further includes frame type indicationinformation.

The processor 3202 is further configured to determine a frame typeaccording to the frame type indication information before thetransmitter 3203 sends the second-type frame to the network device inthe timeslot randomly selected from the second time range.

The transmitter 3203 is specifically configured to send, to the networkdevice in the timeslot randomly selected from the second time range, thesecond-type frame corresponding to the frame type. Transmission durationof frames corresponding to different frame types is different.

Optionally, the broadcast frame further includes frame quantityindication information.

The processor 3202 is further configured to determine a quantity ofto-be-sent frames according to the frame quantity indication informationbefore the transmitter 3203 sends the second-type frame to the networkdevice in the timeslot randomly selected from the second time range.

The transmitter 3203 is specifically configured to successively send theframe quantity of the second-type frames to the network device in thetimeslot randomly selected from the second time range.

Optionally, the broadcast frame further includes usage indicationinformation of at least one channel.

The processor 3202 is further configured to: determine, according to theusage indication information of the at least one channel, whether the atleast one channel is available; and select an available channel from theat least one channel.

The transmitter 3203 is specifically configured to send the second-typeframe to the network device through the available channel in thetimeslot randomly selected from the second time range.

Optionally, the transmitter 3203 is specifically configured to: if theavailable channel is a main channel, send the second-type frame to thenetwork device through the available channel in the timeslot randomlyselected from the second time range.

Optionally, the broadcast frame further includes duration informationcorresponding to each channel.

The processor 3202 is further configured to: if the available channel isa secondary channel, determine, according to duration informationcorresponding to the available channel, a time range corresponding tothe available channel; and randomly select a timeslot from the timerange corresponding to the available channel.

The transmitter 3203 is further configured to send the second-type framethrough the available channel in the timeslot randomly selected from thetime range corresponding to the available channel.

Optionally, the processor 3202 is further configured to randomly selectbackoff duration in the timeslot randomly selected from the second timerange before the transmitter 3203 sends the second-type frame to thenetwork device in the timeslot randomly selected from the second timerange.

The transmitter 3203 is specifically configured to send the second-typeframe to the network device after the backoff duration in the timeslotrandomly selected from the second time range.

Optionally, the processor 3202 is further configured to: before thetransmitter 3203 sends the second-type frame to the network device inthe timeslot randomly selected from the second time range, determine,according to an access priority of the second user equipment, backoffduration corresponding to the access priority. A higher access priorityindicates shorter backoff duration. A lower access priority indicateslonger backoff duration.

The transmitter 3203 is specifically configured to send the second-typeframe to the network device after the backoff duration in the timeslotrandomly selected from the second time range.

Optionally, the processor 3202 is further configured to determine theaccess priority according to a quantity of access failures of the seconduser equipment. A larger quantity of access failures indicates a higheraccess priority.

The user equipment provided in Embodiment 4 of this application mayperform the information transmission method performed by the second userequipment in either Embodiment 1 or Embodiment 2. For a beneficialeffect of Embodiment 4, refer to the foregoing embodiments. Details arenot described herein again.

In addition, functional units in the embodiments of this application maybe integrated into one processing unit, or each of the units may existalone physically, or two or more units are integrated into one unit. Theintegrated unit may be implemented in a form of hardware, or may beimplemented in a form of a software functional unit.

When the integrated unit is implemented in the form of a softwarefunctional unit and sold or used as an independent product, theintegrated unit may be stored in a computer-readable storage medium.Based on such an understanding, the technical solutions of thisapplication essentially, or the part contributing to the prior art, orall or some of the technical solutions may be implemented in a form of asoftware product. The computer software product is stored in a storagemedium and includes several instructions for instructing a computerdevice (which may be a personal computer, a server, a network device, orthe like) or a processor to perform all or some of the steps of themethods described in the embodiments of this application. The storagemedium includes any medium that can store program code, such as a USBflash drive, a removable hard disk, a read-only memory (ROM), a randomaccess memory (RAM), a magnetic disk, or an optical disc.

What is claimed is:
 1. A network device, comprising: a transmitter; anda receiver, wherein the transmitter is configured to send a broadcastframe, wherein: the broadcast frame comprises first duration informationand second duration information; the first duration information isconfigured to indicate a first time range of association beamformingtraining (A-BFT) for a first user equipment, wherein a first timeslot isselected randomly from the first time range; the second durationinformation is configured to indicate a second time range of A-BFT for asecond user equipment, wherein a second timeslot is selected randomlyfrom second time range; the first user equipment and the second userequipment correspond to different communications standards from oneanother; and a duration of the second time range is equal to or greaterthan a duration of the first time range; and wherein the receiver isconfigured to: receive a first-type frame from the first user equipmentin the first timeslot randomly selected from the first time range; andreceive a second-type frame from the second user equipment in the secondtimeslot randomly selected from the second time range; wherein atransmission duration of the first-type frame is greater than atransmission duration of the second-type frame.
 2. The network deviceaccording to claim 1, the second-type frame is a short sector sweep(SSSW) frame.
 3. The network device according to claim 1, wherein thefirst duration information is located in an A-BFT length field of abeacon interval (BI) control field in the broadcast frame; and whereinthe second duration information is located in at least one bit in the BIcontrol field except the A-BFT length field.
 4. The network deviceaccording to claim 1, wherein the broadcast frame further comprisesframe quantity indication information.
 5. The network device accordingto claim 4, wherein the frame quantity indication information isconfigured to indicate a frame quantity of the second-type frame; andwherein the receiver is further configured to receive a quantity ofsecond-type frames from the second user equipment equal to the framequantity of the second-type frame.
 6. The network device as claimed inclaim 5, wherein the frame quantity indication information is furtherconfigured to indicate a frame quantity of the first-type frame; whereinthe receiver is further configured to receive a quantity of first-typeframes from the first user equipment equal to the frame quantity of thefirst-type frame.
 7. The network device as claimed in claim 4, whereinthe frame quantity indication information is located in a frame ofsector sweep (FSS) field of a beacon interval (BI) control field in thebroadcast frame.
 8. A user equipment, comprising: a processor; and atransceiver coupled to the processor, wherein the transceiver isconfigured to receive a broadcast frame from a network device, whereinthe broadcast frame comprises first duration information and secondduration information, wherein the first duration information isconfigured to indicate a first time range of association beamformingtraining (A-BFT) for a first user equipment, wherein a first timeslot isselected randomly from the first time range, wherein the second durationinformation is configured to indicate a second time range of A-BFT for asecond user equipment, wherein a second timeslot is selected randomlyfrom the second time range, wherein the first user equipment and thesecond user equipment correspond to different communications standardsfrom one another, and wherein a duration of the second time range isequal to or greater than a duration of the first time range; wherein theprocessor is configured to determine the second time range and randomlyselect the second timeslot from the second time range; and wherein thetransceiver is further configured to send a second-type frame to thenetwork device in the second timeslot randomly selected from the secondtime range, wherein a transmission duration of a first-type frame sentby the first user equipment in the first timeslot randomly selected fromthe first time range is greater than a transmission duration of thesecond-type frame.
 9. The user equipment according to claim 8, whereinthe second-type frame is a short sector sweep (SSSW) frame.
 10. The userequipment according to claim 8, wherein the first duration informationis located in an A-BFT length field of a beacon interval (BI) controlfield in the broadcast frame; and wherein the second durationinformation is located in at least one bit in the BI control fieldexcept the A-BFT length field.
 11. The user equipment according to claim8, wherein the broadcast frame further comprises frame quantityindication information.
 12. The user equipment according to claim 11,wherein the frame quantity indication information is configured toindicate a frame quantity of the second-type frame; and wherein thetransceiver is further configured to send a quantity of second-typeframes to the network device equal to the frame quantity of thesecond-type frame.
 13. The user equipment as claimed in claim 12,wherein the frame quantity indication information is further configuredto indicate a frame quantity of the first-type frame to be sent by thefirst user equipment.
 14. The user equipment as claimed in claim 8,wherein the frame quantity indication information is located in a frameof sector sweep (FSS) field of a beacon interval (BI) control field inthe broadcast frame.
 15. A non-transitory computer-readable storagemedium storing a computer program that, when executed, causes a computerto execute the following operations: receiving a broadcast frame from anetwork device, wherein the broadcast frame comprises first durationinformation and second duration information, wherein the first durationinformation is configured to indicate a first time range of associationbeamforming training (A-BFT) for a first user equipment, wherein a firsttimeslot is selected randomly from the first time range, wherein thesecond duration information is configured to indicate a second timerange of A-BFT for a second user equipment, wherein a second timeslot isselected randomly from second time range, wherein the first userequipment and the second user equipment correspond to differentcommunications standards from one another, and wherein a duration of thesecond time range is equal to or greater than a duration of the firsttime range; determining the second time range and randomly selecting thesecond timeslot from the second time range; and sending a second-typeframe to the network device in the second timeslot randomly selectedfrom the second time range, wherein a transmission duration of afirst-type frame sent by the first user equipment in the timeslotrandomly selected from the first time range is greater than atransmission duration of the second-type frame.
 16. Thecomputer-readable storage medium according to claim 15, wherein thesecond-type frame is a short sector sweep (SSSW) frame.
 17. Thecomputer-readable storage medium according to claim 15, wherein thebroadcast frame further comprises frame quantity indication information.18. The computer-readable storage medium according to claim 17, whereinthe frame quantity indication information is configured to indicate aframe quantity of the second-type frame; and wherein the operationsfurther include: sending a quantity of second-type frames to the networkdevice equal to the frame quantity of the second-type frame.
 19. Thecomputer-readable storage medium according to claim 18, wherein theframe quantity indication information is further configured to indicatea frame quantity of the first-type frame to be sent by the first userequipment.
 20. The computer-readable storage medium according to claim15, wherein the frame quantity indication information is located in aframe of sector sweep (FSS) field of a beacon interval (BI) controlfield in the broadcast frame.